The ALS Prolog source tree is divided into core and peripheral directories. The core directory contains the source for the Prolog compiler, runtime, and IDE. The peripheral directories contain manuals, examples, extensions, etc. The tree is hosted on GitHub at:

https://github.com/AppliedLogicSystems/ALSProlog

Use git clone https://github.com/AppliedLogicSystems/ALSProlog.git to obtain the tree.

Linux, Unix-like systems, including Mac OS X and Cygwin:

Locate yourself in the toplevel 'unix' directory in the tree, and execute 'make'. When the build completes, you will find a folder

unix/linux/als-prolog	
	or 	
unix/darwin/als-prolog
	or 	
unix/cygwin/als-prolog
	or possibly
unix/<flavor>/als-prolog

where darwin is the Mac OS X flavor of Unix, and <flavor> is possibly some other flavor of unix detected by the build process.

Windows:

Locate yourself in the toplevel 'win32' directory in the tree, and execute 'make'. When the build completes, you will find a folder

win32/als-prolog	

Generally, a GNU/Linux OS with standard build tools (Make, C-compiler, etc), Git, Ruby, Libcurl, and Tcl/Tk. Packages for popular distributions:

Debian/Ubuntu: sudo apt-get update && sudo apt-get install build-essential git gcc-multilib ruby ruby-dev php libcurl4-openssl-dev tk-dev

CentOS/Fedora: sudo yum groupinstall 'Development Tools' && sudo yum install ruby ruby-dev php libcurl tcl-devel tcl tk-devel tk

Xcode command line tools. For version before High Sierra (10.13), a recent version of Ruby is required. Homebrew Ruby is recommended. For versions after Big Sur (11), PHP is required for testing. Homebrew PHP is recommended.

MSYS2 tool-chain is used to build for Win32, with packages:

pacman --sync git base-devel mingw-w64-i686-toolchain mingw-w64-i686-curl zip procps

Ruby installed via RubyInstaller (use recommended Ruby+DevKit version).

PHP installed via PHP Download or elsewhere.